for all \(w,x,y,z \in Q\) , then \(Q\)  is said to be medial. This property can also be expressed as \((wx)(yz) = (wy)(xz)\) ,
and has been referred to by various authors as abelian [1]}, [2]}, [3]} or entropic [4]};
medial appears to be the most modernly accepted term [5]}, [6]}, [7]}, [8]}, and so has been adopted for this paper.
